The research described in this project is directed toward elucidating the structure and mechanism of the enzyme, formyltetrahydrofolate synthetase. Experiments are designed to: 1. Determine the mechanism of the reaction, ie., to identify any enzyme- bound intermediates. 2. Investigate the role of specific cations and anions in maintaining the quaternary structure of the protein. 3. Identify the amino acid residues at the active site of the enzyme.